Reverse-total shoulder arthroplasty cost-effectiveness: A quality-adjusted life years comparison with total hip arthroplasty

Table 1 Markov stochastic model

Component	Abbreviation	Value
Age of THA patients, yr ± SD[7]	AgeH	67.9 ± 9.0
Gender of THA patients, % men, % women[7]	%H-M, %H-W	46%, 54%
Age of RSA patient, yr ± SD	AgeS	69.3 ± 7.7
Gender of reverse shoulder patients, % men, % women	%RSM, %RSW	60%, 40%
Standard reduction in quality of life[9]	SR	-3%
1Pre-operative THA cost, $[7]	Hpreop	400
Pre-operative RSA cost, $[2]	Rpreop	600
1Cost of THA implant, $	Himplant	4300
1THA surgical and hospital costs, $	Hsurg	5600
1Total direct cost of THA, $	dcTHA	Himplant + Hsurg = 9900
1Cost of post-operative implant care, $[7]	Ipostop	1400
1Cost of primary THA, $	cTHA	dcTHA + Hpreop + Ipostop = 11700
Cost of THA revision implant, $[13]	Hrevimplant	%cup × cCup + %liner × cLiner + %stem × cStem = 1700
Average cost of THA revision, $[13]	Hrev	Hsurg + Hrevimplant = 7300
1Cost of RSA implant, $	Rimplant	8900
1RSA surgical, hospital costs, $	Rsurg	6100
1Total direct primary RSA cost, $	dcRSA	Rimplant + Rsurg = 15000
1Primary RSA cost, $	cRSA	dcRSA + Rpreop + Ipostop = 17000
1RSA revision implant cost, $	Rrevimplant	%glenoid × cGS + %Stem × cStem + %poly × cPoly %Hemi × cHemi = 4000
1Average revision RSA cost, $	Rrev	Rsurg + Rrevimplant
The length of first, second, third cycles hip, yr	hCL1, hCL2, hCL3	0.083, 0.416, 0.5
The length of first, second, third cycles shoulder, yr	sCL1, sCL2, sCL3	0.25, 0.25, 0.5
Length of cycle thereafter both, yr	CL	1
Age-specific mortality rate male, female[12]	mAgeM, AgeF	2007 United States life tables
Mortality rate, shoulder	mS	mAgeM × %SM + mAgeF × %SF
Mortality rate, hip	mH	mAgeM × %HM + mAgeF × %HF
THA revision cases[13]	hRev	44
Published cases[13]	hPC	211
THA follow-up years[13]	hFY	13.9 × hPC = 2932
Probability of THA revision/shoulder, yr	Ω1	hRev/hFY = 0.015
RSA revisions[14]	sRev	79
Published cases[14]	sPC	782
RSA follow-up years[14]	sFY	3.5 × sPC = 2737
RSA revision probability per shoulder, yr	Ω2	sRev/sFY = 0.029
Utility, quality of llfe improvement, EQ-5D	pQoL, oQoL	α× PF + β× RP + γ× RE + δ× BP + ε × GH + ζ× VT + η× MH + θ × SF
Utility hip, shoulder	qHwell, qSwell	oQOL - pQOL
The utility associated with a THA revision, QALY	qHrev	0.5 × qHwell
The utility associated with a RSA revision, QALY	qSrev	0.5 × qSwell

¹Norton Healthcare cost data Louisville, KY, United States. RSA: Reverse-total shoulder arthroplasty; QALY: Quality-adjusted life year; THA: Total hip arthroplasty; PF: Physical function; RP: Role physical; RE: Role emotional; BP: Bodily pain; GH: General health; VT: Vitality; MH: Mental health; SF: Social function; oQOL: Post-operative quality of life; pQOL: Pre-operative quality of life.